The present invention relates to an apparatus for controlling a vehicle having diversified control items, such as an automobile and, more particularly, to a vehicle control apparatus suitable for enhancing the safety of an automobile provided with an internal combustion engine, such as a gasoline engine.
Various kinds of controllers using a micro-computer have come to be employed in recent years. A variety of controllers with a micro-computer have now been applied to automobiles for the purposes of controlling the power transmission mechanism and the air conditioner, suspension control, or the like, in addition to various controls concerning the engine, in individual units.
Some conventional unit controllers are provided with a self-diagnosis function and a fail-safe function. However, they have no problem so long as each of the unit controllers exhibits reliably its fail-safe function but does not take into consideration the fact that when any abnormality occurs in any of various load driving circuits controlled by the unit controllers, the fail-safe function cannot be obtained.
For example, "Automobile Engineering" April, 1988, p. 41 roughly discloses that a mutual communication system between computers for control is employed in order to obtain an optimum control. However, the papers do not touch the above mentioned problem. Therefore, the conventional technique has a problem with respect to provision of sufficient reliability.